Tandem rocker mount



July 4, 1961 R. A. JEWELL ET AL TANDEM ROCKER MOUNT Filed Jan. 21, 1960INVENTORS JkfiiAJW/l ATTORNEYS United States Patent j 2,991,065 r TANDEMROCKER MOUNT Robert A. Jewell and Johnny T, Watters, both of P.(). Box1007, Savannah, Ga. r Filed Jan. 21,1960, Ser. No. 3,860 6JClaims. (Cl.267-19) This invention relatesto tandem wheel assemblies, and

particularly to the equalizing rockers of such assemblies and a novelmount therefor.

As is well known, it is common practice-to providean equalizing rockerbetween adjacent ends of a pair of springs in a conventional tandernwheel mount, so that shoclgs to one axle will be transmitted through itsspring to the rocker and from the ro c ker to the other,springof themount to transfer part of the shock to the other axle so as to equalizethe shock between the axles and: permit one axle to compensate formovement of the other. In conventional practice, the rocker is freelypivoted in a hanger which is secured to the vehicle frame. :Although,

ture wherein the rocker is mounted-so as to absorb, shocks and, to someextent, cushion load transference from one axle to. the other. i a

Another object istoprovide a. rocker mount which will bias the rocker toits nonnahinoperative position and provide torque resistance to movementfrom that position.

i A further object is the provision of stnlcture. of this nature whichproduces unique interaction between the pivot pin and rockerand inwhich, a resilient interconnection between thetwo. is made byinsertionof the pin in the rocker. I

Still another object is to provide a resilient interconnection as set'out above in which, during assembly, the resilient member of-theassembly will be automatically pre-stressed to the properdegree.

Yet another object is to providearocker mount of the type describedabove which will substantiallyel iminate noise and rattle duringoperation ofrocker.

Other objects of the invention will become apparent from the followingdescription of one practical embodiment thereof, when taken inconjunction with the drawings which accompany, and form part of, thisspecification.

In the drawings:

FIGURE 1 is a side elevation of a portion of a vehicle frame, showingthe rocker arm and its mounting bracket and associated structure;

FIGURE 2 is a vertical, transverse section through the structure shownin FIGURE 1, and is taken on the line 2-2 of FIGURE 1;

FIGURE 3 is a horizontal section taken on the line 33 of FIGURE 2; and

FIGURE 4 is a vertical section taken on the line 44 of FIGURE 2.

In general, the invention consists in a rocker arm provided with aresilient bushing and a pivot pin which is secured to the bushing andhold against rotative movement, whereby rocking movement of the rockerresults in, and is resisted by, torque action of the bushing, and thebushing acts as a shock absorber for the rocker arm. The invention alsoconcerns the novel arrangement of the parts and their assembly.

r t A more specific object is the provision of such strucg ice Referringto the drawings in detail, there is shown a portion of a bottom siderail, or frame member 1 of a vehicle, with a bracket 2 bolted, orotherwise secured, to the rail. The bracket has an upper web 3' whichfits flush against the vehicle frame and is secured to it, and abifurcated lower section 4providing transversely spaced, depending legs5. The legs have, axially aligned aper tured bosses 6;to receive, apivot pi n 7. The legs S are in the form of rearwardly curving horns andhave at their tips another pair ofaxially aligned apertured bosses 8:

which receive-a pivot pin 9 to fasten one end of a radius Y rod 10, tothe bracket. The opposite end of the rod will i be connected to therear. axle of the vehicle, as is well known.

Anfequalizing rocker 11 is mounted on the pivot pin 7. The rocker has anopening 12 in its central section to receive the pivot pin. The rockerhas arms 13 extending from thecentral portion, from which spaced flangesproject inwardly to, define a channel 14 into which the endsof adjacentsprings 15 are 'slidably mounted. I

In accordance with the present invention, the opening. 12 in the rockerarm is somewhat larger thanthe diameter of the pivot pin. This permitsthe use of a bushing .16 in the opening 12, which serves as ashock-absorbing shield between the pivot pin and rocker and, at; thesame,

ly oversize for the hole 12 in the rocker so that it must.

be compressed slightly to fit into the hole, causing the. areuatesections. of the ring to move closer toward one another.

Pivot pin 7 has a diameter. approximating that of the :H inside of themetal ring. before the rubbersleeve is compressed by pressing into theopening. of the. rocker. arm.

It is necessary, therefore, to provide a tapcredleading end, 21 onthepin to enter between the ring sections. to;

move them apart to the; diameter of the body. of the pin.

The pin is provided with diametrically opposed grooves 22 .to receivethe guide flanges 2Q of the ring. sections. As the sections were pressedtogether by insertion of the.

bushing in the rocker arm, the pairs of flanges2li fwill. be relativelyclosely spaced and will enter freely the grooves 22 on the tapered areaof the pin, as the pin is inserted. As the pin spreads the ringsections, the flanges 20 will come into contact with the side walls ofthe grooves and the sections will be tightly gripped about the curvedwalls of the pin. The spreading of the metal ring will further compressthe rubber sleeve so that it will be firmly compacted, and its outersurface will be tightly bound frictionally to the inner wall of therocker arm opening 12. Thus, the outer surface of the bushing will beheld to the rocker arm and the metal ring will be fixed to the pivotpin, so that no rocking movement of the rocker relative to the pin cantake place unless the rubber sleeve is tortionally twisted. This meansthat the torque of the rubber sleeve will resist all rotative movementof the rocker. It is to be noted that the amount of ultimate compressionof the resilient bushing, and thereby the degree of pre-stressing of thebushing, may be predetermined by the relative diameters of the rockerarm opening 12, the inner and outer diameters of the bushing 16, and thediameter of the pin 7. Thus, the amount of compression of the bushingand the degree of pre-stressing can be accurately predetermined, and theinsertion of the Batentecl July 4, 1961 pin 7 in the bushing willcompress the resilient member thedetermined amount and thusautomatically accomplish the desired prestressing without need foradditional adjustment. t

In order to hold the pivot pin stationary, the bosses 6 of the bracket 2are provided with keys 23 which project into the pivot pin openingsand'which are positioned to fit into the grooves 22 of the pin. As thekeys are provided at both bosses, the pin will be held at both ends andcompletely rigid and stationary. The pin is held, against endwisemovement by cap plates 24 which are bolted to the bosses 6 to overliethe pivot pin ends. The pin is beveled at its bottom at each end, as at25, and the end plates have wedges 26 which enter the openings in thebosses, engage the beveled surfaces 25 of the pivot pin, and lift thepin to bring the bottom sides of the grooves into tight engagement withthe keys 23. This will compensate for play and hold the pin immovable.All noise, rattle and movement will be removed by this arrangement.

It will be seen from the above that the rocker will be mounted upon animmovable pin with a bushing of rub-- ber interposed between the pin androcker. The bushing is frictionally held against rotative movementrelative to the rocker, and positively held by the flanges of the splitring to the pin. All rocking movement of the rocker arm will be resistedby the rubber sleeve, and shocks to the rocker will be absorbed by therubber sleeve. This arrangement will greatly stabilize the rocker armaction, reduce shocks, and substantially eliminate rocker arm noise.

While in the above one practical embodiment of the invention has beendisclosed, it will be understood that the details of structure shown anddescribed are merely for purposes of illustration, and the invention maytake other forms within the scope of the appended claims.

What is claimed is:

'1. A mounting for a tandem rocker arm comprising, a mounting brackethaving a pair of spaced legs provided with openings in axial alignment,keys in the openings with the keys of the openings of two legs alignedwith one another, a rocker arm having an opening intermediate its ends,a rubber sleeve frictionally held within the opening in the rocker arm,a split ring fixed to the inner surface of the rubber sleeve andhavingflanges at the edges of the split ring extending inwardly towardthe center of the ring, a pin extending through the openings in thebracket legs and rocker arm pivotally mounting the-rocker arm betweenthe bracket legs, said pin having a groove lengthwise of its surfaceinto which the keys of the bracket legs seat to hold the pin againstrotation and into which the flanges of the split ring seat to lock thesplit ring to the 2. A mounting for a tandem rocker arm as claimed inclaim 1' wherein the rubber bushing has an outer diameter larger thanthe opening in the rocker arm so that the bushing is compressed withinthe rocker arm opening for tight frictional surface engagement betweenthe bushing and the rocker arm, and the pin has a tapered end forinsertion within the split ring to spread the ring and compress therubber bushing.

3. A mounting for a tandem rocker arm as claimed in claim 2 wherein capplates are secured to the bracket legs overlying the pin ends to preventendwise movement of the pin, the pins are beveled at opposite ends,

, and the caps carry wedges fitting between the beveled ends of the pinand the inner surfaces of the bracket openings to bind the pins in thebracket leg openings.

4. A mounting for a tandem.- rocker arm as claimed in claim 3 whereinthe keys in each bracket leg opening 7 are oppositely opposed, the pinhas a second groove diametrically opposite the first, and the split ringis in two in claim 4 wherein the split ring sections are bonded to therubber bushing.

' silient sleeve and a split ring bonded to the inner surface of thesleeve, means carried by'the split ring engaging the pin to lock thesplit ring to the pin, and cap plates secured to the brackets overlyingthe openings inthe brackets to prevent endwise movement of the pin, thepin having beveled ends and the cap plates carrying wedges fittingbetween the beveled ends of the pin and the inner surfaces of thebracket openings to lift the pin and bind it in the bracket openings.

I References Cited in the file of this patent UNITED STATES PATENTS1,961,536 Thiry June 5, 1934 2,240,709 Mead May 6, 1941 2,749,141Mal-tin June 5, 1956 2,900,197 Hutchens Aug. 18, 1959 FOREIGN PATENTS140,267 Australia Feb. 16, 1951

